keeps printing blank pages or has weird streaks and gaps, even with new cartridges.

Diagnosis

The HP OfficeJet Pro 8135e utilizes a fixed-printhead design, meaning the nozzles are integrated into the machine rather than the cartridges. When you experience blank pages or streaks despite having full ink levels, it is almost always caused by "air locks" or dried ink residue clogging the microscopic nozzles of the printhead. This typically occurs if the printer has sat idle for more than two weeks or if non-genuine ink has left a sticky residue that traps air bubbles. Because this model uses a thermal inkjet process, the ink must be heated to a precise temperature to be ejected. If a tiny air bubble is trapped in the ink delivery tube or if dried ink has formed a "skin" over the nozzle, the ink cannot flow, resulting in horizontal white gaps (banding) or entirely blank pages. You can confirm this by printing a "Print Quality Diagnostic Page"; if specific color blocks are missing or contain thin white lines, the printhead is physically obstructed.

How to Fix It

To resolve this, you must force the printer to purge the air bubbles and clear the dried ink using the internal pump system. Follow these exact steps:

1. On the printer's front touchscreen, swipe down from the top of the screen to open the Dashboard.
2. Select the Settings gear icon, then navigate to Printer Maintenance.
3. Select Clean Printhead. This is the first level of cleaning. Once completed, print a test page.
4. If streaks remain, return to the Printer Maintenance menu and select Clean Printhead - Level 2. This process uses more ink and higher pressure to force clogs out of the nozzles.
5. If the page is still blank, perform a "Hard Power Reset": While the printer is ON, pull the power cord directly from the back of the machine. Wait 60 seconds. Plug it back in and immediately run the Clean Printhead cycle one more time.
6. Print a Print Quality Diagnostic Page (Settings > Printer Maintenance > Reports) to verify that all four color blocks (Cyan, Magenta, Yellow, Black) are solid and free of streaks.

If That Didn't Work

• Manual Printhead Cleaning: If the software cycles fail, remove the ink cartridges and locate the absorbent felt pad in the service station (the area where the cartridges park on the far right). Dampen a lint-free microfiber cloth with distilled water and gently dab the area where the printhead rests to remove accumulated ink sludge that may be preventing the printer from priming itself.
• Check Vent Holes: Inspect the top of your new cartridges. Ensure the orange plastic pull-tabs were removed completely. If a small piece of plastic is still covering the vent hole on top of the cartridge, a vacuum forms inside the tank, preventing ink from flowing to the printhead regardless of how many cleaning cycles you run.
• Flush the Ink Lines: If the printer was unused for months, the ink in the internal tubes may have gelled. Remove the cartridges and use a handheld vacuum or a syringe with a rubber gasket to gently pull air/ink through the intake ports to clear the lines, though this should only be attempted by those comfortable with hardware modification.
• Update Firmware: Occasionally, "blank page" issues are caused by a logic error in the ink delivery system. Go to Settings > Printer Maintenance > Update Firmware to ensure the printer is using the latest ink-jetting algorithms.

Heads Up

• Avoid Frequent Cleaning: Do not run the cleaning cycle more than three times in a row. This consumes a massive amount of ink and can actually cause the printhead to overheat or flood the waste ink pad.
• Print Weekly: To prevent this from recurring, print at least one full-color page every 7-10 days. This keeps the ink moving and prevents the nozzles from drying out.
• Use Distilled Water: If you ever manually clean the printhead area, never use tap water or rubbing alcohol, as the minerals in tap water can cause permanent nozzle crystallization and alcohol can degrade the rubber seals.
• Cartridge Seating: Ensure you hear a distinct "click" when inserting cartridges. A cartridge that isn't fully seated may not create a proper seal, allowing air to enter the system and cause blank pages.